The gastric marginal zone B-cell lymphoma of MALT type

Primary hepatic extranodal marginal zone B-cell mucosa-associated lymphoid tissue lymphoma treated by laparoscopic partial hepatectomy: a case report

BACKGROUND

Primary hepatic extranodal marginal zone B-cell mucosa-associated lymphoid tissue (MALT) lymphoma is very rare, so it is difficult to diagnose preoperatively. And there is no established treatment for hepatic MALT lymphoma. We report herein a case of primary hepatic MALT lymphoma treated by laparoscopic partial hepatectomy, and discuss the usefulness of laparoscopic hepatectomy for a rare liver tumor.

CASE PRESENTATION

This patient was a woman in her 60s, who was diagnosed preoperatively as having synchronous liver metastasis from sigmoid colon cancer; therefore, laparoscopic partial hepatectomy was performed. She had a good course after the operation and was discharged on postoperative day 12. However, she was diagnosed pathologically as having primary hepatic MALT lymphoma. A bone marrow biopsy was also performed, and then she was finally diagnosed as having limited-stage primary hepatic MALT lymphoma. She received no postoperative treatment and showed no recurrence for 4 years postoperatively.

CONCLUSIONS

We experienced the good result of the patient with limited-stage primary MALT lymphoma treated by laparoscopic partial hepatectomy. Liver tumors are sometimes misdiagnosed by imaging examinations alone. Laparoscopic hepatectomy has been widespread recently as a minimally invasive procedure, and it may be useful for both diagnosis and treatment.

Genetic polymorphisms and risk of MALT lymphoma in Greek population

PURPOSE

MALT lymphoma is thought to have a genetic component. Genetic studies in the greek population are rare and genetic determinants remain to be established. The current study aimed to seek correlations between genetic polymorphisms and risk of MALT lymphoma in the Greek population.

PATIENTS AND METHODS

83 MALT lymphoma patients and 60 age-matched healthy outpatients were recruited. SNPs in TNFa, LTA and CTLA-4 genes and IL1RN-VNTR and GSTT1 and GSTTM1 null polymorphisms were genotyped using published PCR/PCR-RFLP methods, while two novel PCR-RFLP methods were developed for IL-22 rs7314777 and TCF19 rs7750641 SNPs. Part of the results was validated by DNA-sequencing. Statistical analysis was performed using SPSS and the SNPstats bioinformatic tool.

RESULTS

The mean age of the patients and controls were 55.9 and 56.2 years respectively. The majority of patients (63) suffered gastric marzinal zone lymphoma (GMZL) and 71.1% were stage I at diagnosis. A statistically significant association was noted for the CTLA-4 49A/ G G variant (OR:2.56,p: 0.006) and the TCF19 rs7750641 SNP T variant (OR: 3.86, p:0.023).

CONCLUSIONS

Our study confirmed a role for CTLA-4 49A/G and TCF19 rs7750641 SNPs in the Greek population. Additional studies could help confirm these associations and possibly link them to prognosis or response to treatment parameters.

[Diagnosis and Treatment of Gastric Mucosa-associated Lymphoid Tissue Lymphoma]

The stomach is the most common primary site of an extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT) type, which is characterized by an indolent clinical course. A diagnosis of gastric MALT lymphoma requires an endoscopic biopsy that should be confirmed by an experienced pathologist. Gastric MALT lymphoma shows a variable endoscopic appearance, including erosion, erythema, discoloration, atrophy, ulcer, and subepithelial lesion. The distribution is often multifocal. Therefore, clinical suspicion and multiple biopsies are essential for an accurate diagnosis. Gastric MALT lymphoma is almost invariably associated with a Helicobacter pylori (H. pylori) infection. H. pylori eradication therapy is the mainstay of treatment, which must be delivered to all patients regardless of the H. pylori infection status or stage. For patients who have failed to achieve remission following eradication therapy, radiotherapy or chemotherapy can be considered. Radiotherapy is an effective treatment modality for a localized stage and shows excellent outcomes. In the presence of disseminated or advanced disease, chemotherapy and/or immunotherapy with the anti-CD20 monoclonal antibody, rituximab, can be applied. Treatment should be individualized according to the stage and symptoms, as well as the patients' preference. Given that the clinical course of gastric MALT lymphoma is usually indolent, watchful waiting may be an adequate strategy in selected cases where scheduled follow-up is guaranteed.

Radiotherapy alone for stage IE ocular adnexal mucosa-associated lymphoid tissue lymphomas: long-term results

Background

To evaluate the long-term efficacy and toxicity of radiation therapy in patients with Stage IE primary ocular adnexal mucosa-associated lymphoid tissue lymphoma.

Methods

We designed a retrospective analysis to evaluate 81 patients with ocular adnexal mucosa-associated lymphoid tissue lymphoma treated with radiation therapy between 2006 and 2016. The median radiation dose was 30 Gy (range, 30–36 Gy in 15–18 fractions). Local control, progression-free survival, overall survival, and cumulative incidence of Grade 3 cataract were calculated by using the Kaplan–Meier method.

Result

The median follow-up time was 74 months (range, 4–157 months). The 5-year local control was 100%. Although local relapse was suspected in 3 patients after radiation therapy, 2 patients were pathologically diagnosed as IgG4-related inflammation and in 1 patient as intense inflammatory cell infiltration. The 5-year progression-free survival was 94.4%. Five patients had relapse at distant sites. The 5-year overall survival was 98.8%. Twenty patients had Grade 3 cataract. The 5-year cumulative incidences of Grade ≥ 3 and Grade ≥ 2 cataract for 58 patients treated without a lens shield were 38 and 40%, respectively. The incidence of Grade ≥ 3 cataract was 42% for 50 patients treated with 6-MV X-rays (estimated lens dose: 29 Gy) and 17% for 8 patients treated with 9-MeV electrons (estimated lens dose: 24 Gy).

Conclusions

Radiation therapy alone yielded excellent local control and long-term survival in Stage IE ocular adnexal mucosa-associated lymphoid tissue lymphoma. Long-term observation with careful attention to relapse at distant sites is necessary. In the case of suspected local relapse, IgG4-related disease should be carefully ruled out.

Genetic contributors and soluble mediators in prediction of autoimmune comorbidity

Comorbidities including subclinical atherosclerosis, neuropsychological aberrations and lymphoproliferation represent a major burden among patients with systemic autoimmune diseases; they occur either as a result of intrinsic disease related characteristics including therapeutic interventions or traditional risk factors similar to those observed in general population. Soluble molecules recently shown to contribute to subclinical atherosclerosis in the context of systemic lupus erythematosus (SLE) include among others B-cell activating factor (BAFF), hyperhomocysteinemia, parathormone (PTH) levels and autoantibodies against oxidized lipids. Variations of the 5, 10- methylenetetrahydrofolate reductase (MTHFR) gene -the main genetic determinant of hyperhomocystenemia in humans-as well the interferon regulatory factor-8 (IRF8), FcγRIIA and BAFF genes have been all linked to subclinical atherosclerosis in SLE. BAFF variants have been also found to confer increased risk for subclinical atherosclerosis and lymphoma development in Sjogren's syndrome (SS) patients. Other genes shown to be implicated in SS lymphoproliferation include genes involved a. in inflammatory responses such as the NFκB regulator Tumor necrosis factor alpha-induced protein 3 (TNFAIP3) and the Leukocyte immunoglobulin-like receptor A3 (LILRA3) immunoreceptor, b. B cell activation and signaling (BAFF/BAFF-receptor), c. type I IFN pathway such as three-prime repair exonuclease 1 (TREX1), d. epigenetic processes including DNA methylation (MTHFR rs1801133, 677T allele) and e. genomic instability (MTHFR rs1801131, 1298C allele). Emerging soluble biomarkers for SS related lymphoma include mediators of B cell growth and germinal center formation such as BAFF, FMS-like tyrosine kinase 3 ligand (Flt-3L) and CXCL13 as well as inflammatory contributors such as inteleukin (IL)-17, IL-18, ASC, LILRA3 and the extracellular lipoprotein-associated phospholipase A2 (Lp-PLA2). In regard to fatigue and neuropsychologic features in the setting of SS, contributing factors such as BAFF variants, antibodies against neuropeptides, proteins involved in nervous system function as well as inflammatory cytokines have been reported.

Associations of Autoimmunity, Immunodeficiency, Lymphomagenesis, and Gut Microbiota in Mice with Knockins for a Pathogenic Autoantibody

A number of mouse strains transgenic for B-cell receptors specific for nucleic acids or other autoantigens have been generated to understand how autoreactive B cells are regulated in normal and autoimmune mice. Previous studies of nonautoimmune C57BL/6 mice heterozygous for both the IgH and IgL knockins of the polyreactive autoantibody, 564, produced high levels of autoantibodies in a largely Toll-like receptor 7-dependent manner. Herein, we describe studies of mice homozygous for the knockins that also expressed high levels of autoantibodies but, unlike the heterozygotes, exhibited a high incidence of mature B-cell lymphomas and enhanced susceptibility to bacterial infections. Microarray analyses and serological studies suggested that lymphomagenesis might be related to chronic B-cell activation promoted by IL-21. Strikingly, mice treated continuously with antibiotic-supplemented water did not develop lymphomas or abscesses and exhibited less autoimmunity. This mouse model may help us understand the reasons for enhanced susceptibility to lymphoma development exhibited by humans with a variety of autoimmune diseases, such as Sjögren syndrome, systemic lupus erythematosus, and highly active rheumatoid arthritis.

Emerging role of infectious etiologies in the pathogenesis of marginal zone B-cell lymphomas

Extranodal marginal zone B-cell lymphomas of the mucosa-associated lymphoid tissue (MALT) arise from lymphoid populations that are induced by chronic inflammation in extranodal sites. The most frequently affected organ is the stomach, where MALT lymphoma is incontrovertibly associated with a chronic gastritis induced by a microbial pathogen, Helicobacter pylori. Gastric MALT lymphoma therefore represents a paradigm for evaluating inflammation-associated lymphomagenesis, which may lead to a deeper understanding of a possible etiologic association between other microorganisms and nongastric marginal zone lymphomas. Besides infectious etiology, chronic inflammation caused by autoimmune diseases, such as Sjögren syndrome or Hashimoto thyroiditis, can also carry a significant risk factor for the development of marginal zone lymphoma. In addition to the continuous antigenic drive, additional oncogenic events play a relevant role in lymphoma growth and progression to the point at which the lymphoproliferative process may eventually become independent of antigenic stimulation. Recent studies on MALT lymphomas have in fact demonstrated genetic alterations affecting the NF-κB) pathway, a major signaling pathway involved in many cancers. This review aims to present marginal zone lymphoma as an example of the close pathogenetic link between chronic inflammation and tumor development, with particular attention to the role of infectious agents and the integration of these observations into everyday clinical practice. See all articles in this CCR Focus section, "Paradigm Shifts in Lymphoma."

Small Bowel Obstruction Due to MALT Lymphoma

Extranodal marginal zone lymphomas comprise approximately 5% of all non-Hodgkin lymphomas. These tumors may arise in any epithelial tissue, including the bowel lining. A report is presented of a patient who presented to the emergency department with epigastric abdominal pain and vomiting. An abdominal sonogram showed a 3.1 cm dilated loop of small bowel near midline just above the umbilicus as well as an abrupt transition zone to normal bowel suggestive of small bowel obstruction, confirmed by subsequent computed tomography. Small bowel resection found an intraluminal tumor, and biopsy showed extranodal marginal zone lymphoma of the mucosa-associated lymphoid tissue (MALT lymphoma).

Marginal zone lymphoma: old, new, targeted, and epigenetic therapies

Marginal zone lymphoma (MZL) is an indolent B-cell lymphoma arising from marginal zone B-cells present in lymph nodes and extranodal tissues. MZL comprises 5-17% of all non-Hodgkin's lymphomas in adults. The World Health Organization categorizes MZL into three distinct types based on their site of impact: (1) splenic marginal zone lymphoma (SMZL); (2) nodal marginal zone lymphoma (NMZL); (3) extranodal mucosa-associated lymphoid tissue (MALT) lymphoma, which can be subdivided into gastric and nongastric. The subgroups of MZL share some common features but are different in their biology and behavior. Owing to the rarity of MZL there are few randomized trials available comparing various treatment options and therefore treatment is controversial, lacking standard guidelines. Treatment should be patient tailored and can range from a 'watchful waiting' approach for asymptomatic patients without cytopenias to surgery or localized radiation therapy. Rituximab in combination with chemotherapy has resulted in longer failure-free survival than chemotherapy alone in patients with SMZL. Helicobacter pylori positive gastric MALT shows a good response rate to triple antibiotic therapy. Newer therapies such as bendamustine, everolimus, lenalidomide, vorinostat and phosphoinositide 3-kinase inhibitors are in clinical trials for patients with relapsed or refractory MZL and have shown promising results. We are presently conducting clinical trials testing the efficacy of the epigenetic activity of cladribine as a hypomethylating agent in combination with the histone deacetylase inhibitor (HDACi) vorinostat and rituximab in patients with MZL. Further studies with the newer agents should be done both in newly diagnosed or relapsed/refractory MZL to streamline the care and to avoid the use of toxic chemotherapies as initial treatment.

Phase II trial of rituximab plus CVP combination chemotherapy for advanced stage marginal zone lymphoma as a first-line therapy: Consortium for Improving Survival of Lymphoma (CISL) study

We conducted a multicenter, phase II trial to investigate the efficacy and safety of rituximab plus CVP (R-CVP) combination therapy for patients with previously untreated stage III or IV marginal zone lymphoma (MZL). The treatment consisted of rituximab 375 mg/m(2), cyclophosphamide 750 mg/m(2) and vincristine 1.4 mg/m(2) (maximum 2.0 mg) being given intravenously on day 1 and oral prednisolone 100 mg on days 1-5. The treatment was repeated every 3 weeks and this was continued for six or eight cycles. Forty-two patients were enrolled from 13 institutes in Korea. Among them, two patients were dropped after the first and second cycles of chemotherapy, respectively, without evaluation. The 40 patients received a total of 287 cycles of R-CVP chemotherapy. The overall response rate was 88% (95% CI, 77-98%) with 24 complete responses (60%). The median duration of response was 28.3 months. After a median follow-up of 38.2 months, the estimated 3-year progression-free survival and overall survival were 59% and 95%, respectively. There were 30/287 cycles (11%) and 5/287 cycles (2%) of grade 3 or 4 neutropenia and febrile neutropenia, respectively. The R-CVP regimen can be an effective and tolerable first-line immunochemotherapy regimen for advanced stage MZL.

Helicobacter pylori-induced activation-induced cytidine deaminase expression and carcinogenesis

Tumorigenesis is a multistep process in which the accumulation of genetic alterations drives the transformation of normal cells into malignant derivatives. Activation-induced cytidine deaminase (AID) contributes to immune system diversity by inducing somatic hypermutations and class-switch recombinations of human immunoglobulin genes. The mutagenic activity of AID, however, can also induce genetic changes in various genes and may lead to the development of cancer. Helicobacter pylori, a class 1 carcinogen for human gastric cancer, affects AID expression by two different mechanisms, introduction of bacterial virulence factors into host cells and induction of inflammatory responses, thereby contributing to the accumulation of mutations in tumor-related genes. Aberrant AID activity may therefore be a novel link between infection and carcinogenesis.

Small intestinal cancer: a population-based study of incidence and survival patterns in the United States, 1992 to 2006

BACKGROUND

The etiology of cancers of the small intestine is largely unknown. To gain insight into these rare malignancies, we evaluated contemporaneous incidence and survival patterns.

METHODS

Using small intestine cancer data from 12 population-based registries of the Surveillance, Epidemiology and End Results Program, we calculated age-adjusted and age-specific incidence rates (IRs), IR ratios, and relative survival (RS) rates.

RESULTS

In total, 10,945 small intestine cancers (IR = 2.10/100,000 person-years) were diagnosed during 1992 to 2006, including carcinomas (n = 3,412; IR = 0.66), neuroendocrine cancers (n = 4,315; IR = 0.83), sarcomas (n = 1,084; IR = 0.20), and lymphomas (n = 2,023, IR = 0.38). For all histologic groups, males had significantly higher IRs than females, and distinct age-specific gender patterns were limited to intermediate-/high-grade lymphomas. Neuroendocrine cancer rates varied significantly by race, with rates highest among blacks and lowest among Asians/Pacific Islanders. Carcinoma IRs were highest among blacks; sarcoma IRs were highest among Asians/Pacific Islanders; and lymphoma IRs were highest among whites. Age-specific IR patterns were similar across racial/ethnic groups. During 1992 to 2006, duodenal cancer IRs increased more markedly than those for other subsites. RS varied little by gender or race. Neuroendocrine cancers had the most favorable RS, and carcinomas had the least favorable. The greatest improvement in 5-year RS from 1992 to 1998 to 1999 to 2005 was observed for sarcomas and lymphomas.

CONCLUSIONS

Distinct small intestine cancer IR patterns according to histologic subtype suggest different underlying etiologies and/or disease biology, with susceptibility varying by gender, racial/ethnic groups, and subsite. Temporal patterns support a possible role for diagnostic bias of duodenal cancers.

IMPACT

Future epidemiologic studies of small intestine cancer should consider histologic subtype by gender, race/ethnicity, and subsite.

MALT lymphoma of the rectum, presenting with rectal prolapsus: a case report

Up to now, there have been only a few reported cases of Mucosa-associated lymphoid tissue (MALT) lymphomas arising in the rectum. Its clinical presentation is indistinguishable from that of rectal carcinoma but the treatment is apparently different. Symptoms of primary lymphomas involving the rectum include; anorexia, weight loss, change in bowel habits, obstruction, and bleeding. These symptoms are not disease specific and can be seen in many other gastrointestinal disorders. Patients with polypoid masses may present with obstruction symptoms. In this rare case, a female patient admitted to the emergency service with prolapsus of a rectal mass.

The optimal treatment of rectal MALT lymphoma is not well defined yet, given the rarity of the disease. Surgical resection of the localized lesion and following adjuvant chemotherapy has proved to be an effective treatment option. However, a close and long-lasting follow-up is important.

Subcutaneous 'lipoma-like' B-cell lymphoma associated with HCV infection: a new presentation of primary extranodal marginal zone B-cell lymphoma of MALT

BACKGROUND

Hepatitis C virus (HCV) infection has been linked to lymphoproliferative disorders. Marginal zone B-cell lymphoma (MZL) represents one of the most frequent lymphoma subtypes associated with HCV infection. We describe an unusual subset of HCV-associated MZL characterized by subcutaneous presentation.

MATERIALS AND METHODS

A series of 12 HCV-positive patients presenting with subcutaneous nodules that revealed lymphoma infiltration at biopsy. Molecular analysis of immunoglobulin heavy chain (IGH) gene rearrangement and FISH investigations for t(11;18)(q21;q21) and t(14;18)(q32;q21) were carried out in nine patients.

RESULTS

The 12 patients (median age 69.5 years), all with positive HCV serology, presented with single or multiple subcutaneous nodules resembling lipomas. Histologically the lesions showed lymphoid infiltrates, consistent with extranodal MZL of mucosa-associated lymphoid tissue (MALT). Functional IGH gene rearrangements were identified in nine tested patients, with somatic mutations in 82%, indicating a histogenesis from germinal center-experienced B cells. The t(11;18) was found in two of nine cases. Staging did not show any other lymphoma localization. In two patients, a response was achieved with antiviral treatment. Extracutaneous spread to MALT sites occurred in a case.

CONCLUSIONS

Our observations expand the spectrum of HCV-associated lymphomas to include a subset of extranodal MZL characterized by a novel primary 'lipoma-like' subcutaneous presentation and indolent clinical course.

TRAF2-binding BIR1 domain of c-IAP2/MALT1 fusion protein is essential for activation of NF-kappaB

Marginal zone mucosa-associated lymphoid tissue (MALT) B-cell lymphoma is the most common extranodal non-Hodgkin lymphoma. The t(11;18)(q21;q21) translocation occurs frequently in MALT lymphomas and creates a chimeric NF-kappaB-activating protein containing the baculoviral IAP repeat (BIR) domains of c-IAP2 (inhibitor of apoptosis protein 2) fused with portions of the MALT1 protein. The BIR1 domain of c-IAP2 interacts directly with TRAF2 (TNFalpha-receptor-associated factor-2), but its role in NF-kappaB activation is still unclear. Here, we investigated the role of TRAF2 in c-IAP2/MALT1-induced NF-kappaB activation. We show the BIR1 domain of c-IAP2 is essential for NF-kappaB activation, whereas BIR2 and BIR3 domains are not. Studies of c-IAP2/MALT1 BIR1 mutant (E47A/R48A) that fails to activate NF-kappaB showed loss of TRAF2 binding, but retention of TRAF6 binding, suggesting that interaction of c-IAP2/MALT1 with TRAF6 is insufficient for NF-kappaB induction. In addition, a dominant-negative TRAF2 mutant or downregulation of TRAF2 achieved by small interfering RNA inhibited NF-kappaB activation by c-IAP2/MALT1 showing that TRAF2 is indispensable. Comparisons of the bioactivity of intact c-IAP2/MALT1 oncoprotein and BIR1 E47A/R48A c-IAP2/MALT1 mutant that cannot bind TRAF2 in a lymphoid cell line provided evidence that TRAF2 interaction is critical for c-IAP2/MALT1-mediated increases in the NF-kappaB activity, increased expression of endogenous NF-kappaB target genes (c-FLIP, TRAF1), and resistance to apoptosis.

Extranodal lymphoma

Lymphomas arising in extranodal sites are intriguing. The types of lymphomas encountered vary widely from one extranodal site to another. For many types of extranodal lymphomas, there are distinctive clinicopathologic features, sometimes including association with an underlying immunodeficiency syndrome, autoimmune disease, infection, or other immunologic disorder, or a predilection to affect patients of certain ethnic origins. Presented below is a review of lymphomas that are encountered most often in extranodal sites.

Helicobacter pylori strikes again: gastric mucosa-associated lymphoid tissue (MALT) lymphoma

Infection with Helicobacter pylori is common. Over 50% of the world's population is estimated to be colonized with the bacteria. The association between Helicobacter pylori and gastric mucosa-associated lymphoid tissue (MALT) lymphoma is well documented. Anti-Helicobacter pylori treatment and the successful eradication of the bacteria can potentially cure patients who test positive for the bacteria and who are diagnosed with low-grade gastric MALT lymphoma. The purpose of this article is to review the evidence implicating Helicobacter pylori as a causal pathogen for the development of gastric MALT lymphoma and to determine that anti-Helicobacter pylori therapy is an effective first-line treatment. The clinical presentation, endoscopic findings, diagnosis, staging, treatment, and follow-up of patients with gastric MALT lymphoma who are treated with anti-Helicobacter pylori therapy are also discussed.

Aberrant NF-kappaB signaling in lymphoma: mechanisms, consequences, and therapeutic implications

The transcription factor NF-kappaB is a tightly regulated positive mediator of T- and B-cell development, proliferation, and survival. The controlled activity of NF-kappaB is required for the coordination of physiologic immune responses. However, constitutive NF-kappaB activation can promote continuous lymphocyte proliferation and survival and has recently been recognized as a critical pathogenetic factor in lymphoma. Various molecular events lead to deregulation of NF-kappaB signaling in Hodgkin disease and a variety of T- and B-cell non-Hodgkin lymphomas either up-stream or downstream of the central IkappaB kinase. These alterations are prerequisites for lymphoma cell cycling and blockage of apoptosis. This review provides an overview of the NF-kappaB pathway and discusses the mechanisms of NF-kappaB deregulation in distinct lymphoma entities with defined aberrant pathways: Hodgkin lymphoma (HL), diffuse large B-cell lymphoma (DLBCL), mucosa-associated lymphoid tissue (MALT) lymphoma, primary effusion lymphoma (PEL), and adult T-cell lymphoma/leukemia (ATL). In addition, we summarize recent data that validates the NF-kappaB signaling pathway as an attractive therapeutic target in T- and B-cell malignancies.

Multifocal extranodal mucosa-associated lymphoid tissue lymphoma affecting the larynx

OBJECTIVES

Extranodal marginal B-cell lymphoma of mucosa-associated lymphoid tissue (MALT) accounts for about 7% to 8% of all B-cell lymphomas and 50% of all gastric lymphomas. Long-term localized growth is typical of MALT lymphoma. Multifocal manifestations are possible in advanced stages. MALT lymphoma of the larynx is a very rare disease; only 15 cases have been reported in the literature.

METHODS

We report a case of multifocal MALT lymphoma affecting the larynx associated with extraesophageal reflux, chronic laryngitis, and gastric Helicobacter pylori infection. The staging revealed a recurrent tumor of MALT lymphoma in the stomach and an involvement of the right conjunctiva.

RESULTS

Following recent reports on successful treatment of MALT lymphoma with antibiotics, initial empirical therapy with doxycycline calcium led to a subjective clinical symptom improvement but no objective response as assessed by laryngoscopy, magnetic resonance imaging of the larynx, and esophagogastroduodenal endoscopy. Because of the advanced stage and multiple extranodal manifestations of the MALT lymphoma, the patient received 3 cycles of chemoimmunotherapy according to the FCR protocol (fludarabine phosphate-cyclophosphamide-rituximab). No evidence of disease was observed after a 6-month follow-up.

CONCLUSIONS

In the rare diagnosis of MALT lymphoma of the larynx, comprehensive staging is indispensable to exclude multifocal involvement. In contrast to the treatment of primarily localized MALT lymphoma, multifocal disease warrants systemic therapy.

A dual role for the API2 moiety in API2-MALT1-dependent NF-kappaB activation: heterotypic oligomerization and TRAF2 recruitment

Mucosa-associated lymphoid tissue (MALT) lymphoma is the most common extranodal lymphoid neoplasm. Chromosomal translocation t(11;18)(q21,q21) is found in 30% of gastric MALT lymphomas and is associated with a failure to respond to standard treatment and a tendency to disseminate. This translocation generates a chimeric protein composed of N-terminal sequences of Inhibitor of Apoptosis 2 (API2, also known as BIRC3 and cIAP2) fused to C-terminal sequences of MALT1. API2-MALT1 promotes cell survival and proliferation via activation of nuclear factor-kappaB (NF-kappaB). Here, we investigate the mechanism by which the API2 moiety contributes to NF-kappaB stimulation. We find that the API2 moiety mediates oligomerization of API2-MALT1 as well as interaction with tumor necrosis factor receptor-associated factor 2 (TRAF2). Surprisingly, oligomerization does not occur via homotypic interaction; rather, the API2 moiety of one monomer interacts with the MALT1 moiety of another monomer. Further, the specific region of the API2 moiety responsible for mediating oligomerization is distinct from that mediating TRAF2 binding. Although deletion or mutation of the TRAF2 binding site does not inhibit oligomerization, it does lead to dramatically decreased NF-kappaB activation. Deletion of both TRAF2 binding and oligomerization regions results in near-complete loss of NF-kappaB activation. Thus, API2 moiety-mediated heterotypic oligomerization and TRAF2 binding both contribute to maximal API2-MALT1-dependent NF-kappaB stimulation.

Non-Hodgkin's lymphoma of mucosa-associated lymphoid tissue

The concept of mucosa-associated lymphoid tissue (MALT) lymphomas was introduced by Isaacson and Wright [Cancer 1983; 52:1410-1416] in 1983. After more than 20 years of clinical research MALT lymphomas are now recognized as a distinct subtype of non-Hodgkin's lymphoma (NHL) with unique pathogenic, histological, and clinical features. Although this subtype of NHL occurs frequently, optimal management remains elusive. This manuscript reviews features of the clinical presentation, diagnosis, pathology, molecular characteristics, and management of both gastric and non-gastric MALT lymphoma.

Prevalence of HCV infection in nongastric marginal zone B-cell lymphoma of MALT

BACKGROUND

Hepatitis C virus (HCV) infection is frequently associated with B-cell non-Hodgkin's lymphomas. We investigated the prevalence of HCV infection in nongastric marginal zone lymphomas of mucosa-associated lymphoid tissue (MALT) in order to define the relationship between the viral infection and the presenting features, treatment, and outcome.

METHODS

We retrospectively studied 172 patients with a histological diagnosis of marginal zone B-cell lymphoma of MALT, except for stomach, and with available HCV serology, among a series of 208 patients.

RESULTS

HCV infection was documented in 60 patients (35%). Most HCV-positive patients (97%) showed a single MALT organ involvement. HCV-positive patients showed a more frequent involvement of skin (35%), salivary glands (25%), and orbit (15%). The majority of stage IV HCV-positive patients (71%) had a single MALT site with bone marrow involvement. The overall response rate was similar in HCV-positive (93%) and HCV-negative patients (87%). Overall survival (OS) and event-free survival (EFS) did not differ according to HCV infection. In multivariate analysis, advanced disease (stage III-IV) was associated with a poorer OS (P = 0.0001), irrespective of HCV serostatus.

CONCLUSIONS

This study shows that nongastric marginal zone lymphomas are characterized by a high prevalence of HCV infection. Patients with involvement of a single MALT site have the highest prevalence of HCV. HCV-positive nongastric lymphomas of MALT show an indolent course similar to HCV-negative patients and seem an ideal target for exploiting the antilymphoma activity of antiviral treatments.

Is endoscopic ultrasound clinically useful for follow-up of gastric lymphoma?

BACKGROUND

Endoscopic ultrasound (EUS) is considered the best technique for locoregional staging at diagnosis but its role in the follow-up of patients with gastric lymphoma after organ-conserving strategies has not been established.

DESIGN AND METHODS

We retrospectively evaluated 23 patients with primary gastric lymphoma treated with a stomach-conservative approach. Sixteen of them were affected by MALT lymphoma and seven by diffuse large-B-cell lymphoma (DLBCL). Five patients were treated with Helicobacter pylori (HP) eradication therapy alone (omeprazole + amoxicillin + clarithromycin); eight patients received a treatment including HP eradication and chemotherapy and the remaining 10 patients were treated with chemotherapy alone.

RESULTS

At the end of treatment, a complete remission was documented in 21 (91%) patients by endoscopy with biopsy (E-Bx) but in only seven (30%) patients by EUS. A total of 99 evaluations with both EUS and E-Bx were evaluated and we found concordance between the two methods in 33 occasions (33%) only. No significant difference on the percentage of concordance was recorded between MALT and DLBCL. After a median follow-up of 36.5 months we have not observed any relapse in 12 patients (six DLBCL and six MALT) with a persistent positive EUS but negative E-Bx.

CONCLUSIONS

Although the length of follow-up cannot exclude late relapse, we think that in restaging and follow-up of gastric lymphoma, EUS seems not to be a reliable tool if it is abnormal and E-Bx still remains the gold standard. Therefore, after conventional conservative treatment, persistence of EUS abnormality with a negative histology should not be considered as a clinically relevant persistence of disease and should not be a reason for further treatment.

FAS (CD95) mutations are rare in gastric MALT lymphoma but occur more frequently in primary gastric diffuse large B-cell lymphoma

A loss of FAS (CD95) function has been proposed to constitute an important step in early mucosa-associated lymphoid tissue (MALT) lymphoma development and FAS mutations have been recognized in malignant lymphomas, in particular at extranodal sites. Since primary gastric lymphomas frequently exhibit resistance to FAS-mediated apoptosis, we investigated whether FAS is mutated in 18 gastric MALT lymphomas and 28 diffuse large B-cell lymphomas (DLBCL). We detected seven mutations in five lymphomas, one MALT lymphoma and four DLBCL; two DLBCL had two mutations. The MALT lymphoma exhibited a point mutation in the splice donor region of intron 3. Three DLBCL had missense mutations in exon 2, which encodes a signal peptide and a portion of the extracellular FAS ligand-binding domain. One DLBCL carried a point mutation in the splice donor region of intron 8, which would result in exon skipping. Two DLBCL harbored a missense mutation in exon 9, which encodes the intracellular death domain. The two death domain mutations inhibited FAS ligand-induced apoptosis in a dominant-negative mode, when transiently expressed in human T47D breast carcinoma and Jurkat T cells. A signal peptide and an extracellular domain mutation, however, failed to inhibit apoptosis in these transfection assays. They are likely to reduce apoptosis in lymphoma cells solely by a loss of function. In summary, our data show that FAS mutations are rare in primary gastric MALT lymphomas (5.6%) but occur in a subset of primary gastric DLBCL (14.3%) and suggest that these mutations contribute to the pathogenesis of gastric lymphomas by rendering lymphocytes resistant to apoptosis.

Gastrointestinal lymphoma

The ability to make treatment recommendations for patients with gastrointestinal lymphoma is hampered by a lack of prospective trials and by a lack of uniformity in classification and staging. Patients with gastric diffuse large B-cell lymphoma have traditionally been treated with surgery and many physicians continue to recommend this approach. However, recent data suggest that these patients can be treated with combination chemotherapy regimens in the same manner as patients with nodal presentations of diffuse large B-cell lymphoma. There is evidence to suggest that adjuvant radiotherapy may improve the outcome for these patients. The recognition that extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue is a distinct clinicopathologic entity and the elucidation of the pathogenic role of Helicobacter pylori has revolutionized the treatment of these gastric lymphomas. Patients with localized disease should be managed with antibiotic therapy initially. Radiation therapy is extremely effective for these patients, but it should probably be reserved for patients who fail anti-H. pylori treatment.

MALT Lymphomas

Mucosa-associated lymphoid tissue (MALT) lymphomas occur in a variety of organs, including the orbit, conjunctiva, salivary glands, skin, thyroid gland, lungs, stomach, and intestine. These tumors are often localized and of indolent clinical behavior. Diagnosis is made by pathologic evaluation of a tissue biopsy. Careful staging is mandatory and tailored to the initial presentation. Staging includes a history and physical, chemistries, computed tomography scan, and bone marrow biopsy. This information is supplemented with an ear, nose, and throat consultation, esophagogastro-duodenoscopy, colonoscopy, endoscopic ultrasound of the stomach, and cytogenetic/immunohistochemical analysis of the tumors. Treatment is tailored to organ involvement and stage at presentation. Eradication of Helicobacter pylori using a triple anti-H. pylori regimen approved by the US Food and Drug Administration is standard therapy for all H. pylori-positive gastric MALT lymphomas. Endoscopic ultrasound- and computed tomography-staged gastric MALT stage IE tumors will achieve a complete response with this approach in approximately 60% to 90% of patients (the more superficial the tumor, the better the response). Patients with tumors that are T4 node-positive Musshoff stage IIE1 and IIE2 or tumors with adverse cytogenetics should receive radiotherapy or surgery with or without radiotherapy. Tumors with a significant high-grade component or large cell tumors with a minor low-grade MALT component should receive CHOP (cyclophosphamide, doxorubicin, vincristine, and prednisone)-based chemotherapy. Localized MALT lymphomas of the orbit, conjunctiva, salivary glands, and thyroid gland are treated successfully with radiotherapy. Surgery as first-line therapy for gastric MALT lymphomas was replaced by attempts at organ preservation. In the past, margin-free surgical excision or tumor debulking followed by radiation therapy and chemotherapy has been highly effective for gastric MALT lymphomas. Therefore, surgical excision of large cell or bulky tumors of the stomach, thyroid, lung, and salivary gland, followed by adjuvant radiotherapy or chemotherapy, may still be an important consideration in selected patients. Surgery still has a role for patients with relapsed or refractory low-grade disease and life-threatening hemorrhage. Disseminated MALT lymphomas are incurable and are treated primarily with chemotherapy according to symptoms.

Dural marginal zone lymphoma with massive amyloid deposition: rare low-grade primary central nervous system B-cell lymphoma. Case report

The authors report the case of a 63-year-old woman who presented with a primary dural extranodal marginal zone lymphoma (MZL) associated with massive kappa light chain amyloidosis of the meninges. Extranodal MZL is a low-grade B-cell lymphoma that may show variable degrees of plasmacytic differentiation. Like solitary plasmacytoma of soft tissue, which can also be associated with amyloid, extranodal MZL generally responds well to local therapy and has a good prognosis. It is important to distinguish these entities from high-grade primary central nervous system (CNS) B-cell lymphomas and more aggressive and/or widespread, potentially amyloidogenic conditions such as multiple myeloma, lympho-plasmacytoid lymphoma, and chronic lymphocytic leukemia/small lymphocytic lymphoma. To the authors' knowledge this is the first reported case of dural MZL associated with massive meningeal amyloid deposition. Extranodal MZL is a rare low-grade primary CNS B-cell lymphoma that may be associated with amyloidosis. It should be considered in the differential diagnosis of CNS lymphoproliferative lesions and CNS amyloidosis.

Gastric MALT lymphoma: from aetiology to treatment

The development of gastric mucosa-associated lymphoid tissue (MALT) lymphoma is dependent on Helicobacter pylori infection. Bacterial colonisation of the gastric mucosa triggers lymphoid infiltration and the formation of acquired MALT. The bacterial infection induces and sustains an actively proliferating B-cell population through direct (autoantigen) and indirect (intratumoral T cells specific for H. pylori) immunological stimulation. Moreover, the bacterial infection provokes a neutrophilic response, which causes the release of oxygen free radicals. These reactive species may promote the acquisition of genetic abnormalities and malignant transformation of reactive B cells. A transformed clone carrying the translocation t(1;18)(q21;q21) forms a MALT lymphoma, the growth of which is independent of H. pylori and will not respond to bacterial eradication. Malignant clones without t(11;18)(q21;q21), but with other genetic abnormalities, such as trisomy 3 or microsatellite instability, depend critically on immune stimulation mediated by H. pylori for their clonal expansion. In the early stages, the tumour can be successfully treated by eradication of the bacterium, whereas at later stages the tumour may escape its growth dependency through acquisition of additional genetic abnormalities such as t(1;14)(p22;q32) and t(1;2)(p22,p12) involving the BCL-10 gene. Finally, further genetic abnormalities, such as inactivation of the tumour suppressor genes, p53 and p16, can lead to high-grade transformation. Detection of these abnormalities may help with the clinical management of patients with gastric MALT lymphoma.

Bimp1, a MAGUK family member linking protein kinase C activation to Bcl10-mediated NF-kappaB induction

Bcl10 and MALT1, products of distinct chromosomal translocations in mucosa-associated lymphoid tissue lymphoma, cooperate in activating NF-kappaB. Mice lacking Bcl10 demonstrate severe immunodeficiency associated with failure of lymphocytes to activate nuclear factor kappaB (NF-kappaB) in response to antigen receptor stimulation and protein kinase C activation. We characterize Bimp1, a new signaling protein that binds Bcl10 and activates NF-kappaB. Bimp1-mediated NF-kappaB activation requires Bcl10 and IkappaB kinases, indicating that Bimp1 acts upstream of these mediators. Bimp1, Bcl10, and MALT1 form a ternary complex, with Bcl10 bridging the Bimp1/MALT1 interaction. A dominant negative Bimp1 mutant inhibits NF-kappaB activation by anti-CD3 ligation, phorbol ester, and protein kinase C expression. These results suggest that Bimp1 links surface receptor stimulation and protein kinase C activation to Bcl10/MALT1, thus leading to NF-kappaB induction.

MALT Lymphomas

This review addresses the biology and the treatment of lymphomas arising from mucosa-associated lymphoid tissue (MALT). This entity, first described in 1983, represents about 8% of all non-Hodgkin's lymphomas and was recently re-classified as "extranodal marginal zone lymphomas of MALT-type." The term marginal zone lymphoma (MZL) encompasses the three closely related lymphoma subtypes of nodal, primary splenic and extranodal lymphomas of MALT type: the latter represent the vast majority of MZL. These lymphomas arise at different anatomic sites, are composed of mature B-cells lacking expression of CD5 and CD10, often present with overlapping morphologic features, but typically quite distinct clinical behaviors. Only very recently cytogenetic/molecular genetic observations have underlined the distinctiveness of these three lymphoid neoplasms, which in both the R.E.A.L. and WHO-classifications are included in the general term of MZL. MALT lymphomas arise in numerous extranodal sites, but gastric MALT lymphoma is the most common and best studied and is, therefore, the paradigm for the group as a whole. Dr. Isaacson describes the principal histological features of these lymphomas, including criteria to distinguish this entity from other small B-cell lymphomas. Several lines of evidence suggest that gastric lymphoma arises from MALT acquired as the result of aH. pyloriinfection. However, at least 1/3 of cases do not respond to eradication ofH. pylori. Very recent data suggest that both t(11;18) (q21;q21) and bcl10 nuclear expression are associated with failure to respond to this treatment. Dr. Gascoyne discusses the biologic function of proteins deregulated through the different translocations, which play a role in pathogenesis of MALT lymphomas, emphasizing particularly their influence in disrupting the apoptotic pathway. Dr. Zucca reviews findings suggesting that MALT lymphoma is an antigen driven neoplasm. He also presents specific guidelines for treatment of gastric lymphomas trying to shed some light on the amazingly inconsistent and confusing data in the literature. Taking advantage on the more than 300 non-gastric MALT lymphomas collected by the International Extranodal Lymphoma Study Group (ILESG), Dr. Cavalli compares gastric lymphomas with those arising in many other sites. Overall, the data presented in this session will underline the fact, that MALT lymphomas are characterized by some unique biological properties.